Monthly Archives: April 2012

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This study aimed to investigate this behavioral facilitation in the context of a learning paradigm by giving tDCS over rIFG repetitively over four consecutive days of training on a behavioral inhibition task (stop signal task (SST)). Twenty-two participants took part; ten participants were assigned to receive anodal tDCS (1.5 mA, 15 min), 12 were assigned to receive training but not active stimulation. There was a significant effect of training on learning and performance in the SST, and the integration of the training and rIFG-tDCS produced a more linear learning slope. Better performance was also found in the active stimulation group. Our findings show that tDCS-combined cognitive training is an effective tool for improving the ability to inhibit responses. The current study could constitute a step toward the use of tDCS and cognitive training as a therapeutic tool for cognitive control impairments in conditions such as attention-deficit hyperactivity disorder (ADHD) or schizophrenia.

Our results indicate that only anodal stimulation of the left prefrontal cortex, but not cathodal stimulation of left DLPFC or anodal stimulation of M1, increases the accuracy of the task performance when compared to sham stimulation of the same area. This accuracy enhancement during active stimulation cannot be accounted for by slowed responses, as response times were not changed by stimulation. Our results indicate that left prefrontal anodal stimulation leads to an enhancement of working memory performance. Furthermore, this effect depends on the stimulation polarity and is specific to the site of stimulation. This result may be helpful to develop future interventions aiming at clinical benefits.

The aim of this study was to assess the differences in the effects induced by tDCS applied to frontal and temporo-parietal areas on phonemic and semantic fluency functional networks in patients with PD.

Functional connectivity in verbal fluency and deactivation task-related networks was significantly more enhanced by tDCS to DLPFC than to TPC. In addition, DLPFC tDCS increased performance on the phonemic fluency task, after adjusting for baseline phonemic performance.

Conclusions

These findings provide evidence that tDCS to specific brain regions induces changes in large scale functional networks that underlay behavioural effects, and suggest that tDCS might be useful to enhance phonemic fluency in PD.

The goal of NS2 is to translate high spatial and temporal resolution brain imaging, fMRI, MEG, and noninvasive brain stimulation into viable solutions for training soldiers and intelligence professionals to help them with real-time decision making and actions that avert injury and trauma. Noninvasive brain stimulation, specifically transcranial direct current stimulation (TDCS), is being used to attempt to influence the learning process, perhaps increasing the speed of learning or improving retention. TDCS utilizes scalp electrodes to deliver low amplitude direct currents to localized areas of the cerebral cortex (the superficial part of the brain), thereby modulating the level of excitability, or, put another way, increasing or decreasing the probability that neurons will talk to each other. “Even though TDCS has been applied to humans safely for decades, we are just beginning to learn how it helps to accelerate the learning process. Within the next couple of years, I expect great progress toward this goal,” says researcher Dr. Michael Weisend.

I called Weisend recently to see what he thought of people experimenting with tDCS. “In the DIY crowd they don’t have the neuroimaging to start the process and know where to place the electrodes,” he told me. “Their success and their safety are going to be limited.” In the laboratory, subjects go through two or three sessions of tDCS over a week. What happens long term if you do more than that? Nobody knows. And the equipment you order from some random person online may not be as reliable as what’s used in a laboratory.

That said, Weisend believes tDCS can be done safely, and he thinks it might be used to prevent memory loss in the elderly or to help patients recover from traumatic brain injuries. He’s tried tDCS on his own brain hundreds of time and hasn’t suffered any deleterious effects—with the notable exception of a few skin burns that were severe enough to leave scars. “You get attached to your work, I guess,” he says.

Not sure how accurate this statement is, but it’s a good way to think of it.
“tDCS changes the voltage across neurons and can make them more or less likely to fire.”
Interesting… use TMS to disrupt the function (for discovery) and tDCS to enhance it!

His team “short-circuited” this area using transcranial magnetic stimulation (TMS) – a stream of magnetic pulses which temporarily disables a targeted area of the brain. The result, they found, was that people’s ability to perform numerical tasks fell. In fact, their performance resembled people with dyscalculia, who have difficulty comprehending mathematics.

Now they have done the reverse, and improved the brain’s arithmetical abilities. To do this the team applied transcranial direct current stimulation (tDCS), a way of enhancing brain activity using an electric current, to the right parietal cortex while simultaneously using the opposite current to subdue activity in the left parietal cortex.

This is such an incredible opportunity for a crowd-sourced neuroscience experiment. Once we can build or buy our own devices, we’ll need a standardized set of problems to test with. If all that data collected to one place… It boggles the imagination!

They gave 28 healthy right-handed participants aged 19-63 the nine-dot problem to solve. Before brain stimulation, 0 out of 22 participants solved the problem. Then they used transcranial direct current stimulation tDCS, which is a safe, non-invasive technique that can increase or decrease cortical excitability and spontaneous neuronal firing in targeted regions. Specifically, they simultaneously decreased excitability of the left anterior temporal lobe ATL while they increased the excitability of the right anterior temporal lobe ATL.

After 10 minutes of right lateralizing tDCS, more than 40 percent of the participants got the problem correct. For contrast, they placed sponge electrodes in the same positions of 11 other participants but they turned off the electrical current after 30 seconds. Therefore, these ‘control’ participants received the exact same experience as those in the active condition but didn’t actually have their brain zapped. None 0/11 of the folks in this placebo condition solved the problem at any point during the experiment.

The Soterix website and all that shiny new technology!
They make reference to ‘HD-tDCS‘ and diagram multi-electrode application for fine-tuning current distribution. Download their device manual (pdf).
Prof. Bikson’s lab has a YouTube page. They seem to have constructed a computer model for determining where current flows according to how electrodes are placed.

Prof. Bikson’s group uses a range of research and engineering design tools including cellular and animal studies, computer simulations, imaging, and clinical evaluation. Prof. Bikson’s research has recieved support from funding agencies including NIH (NINDS,NCI,NIGMS), The Andy Grove Foundation, The Wallace H. Coulter Foundation, and the Howard Hughes Medical Institute. . Prof. Bikson is actively involved in biomedical education including outreach to underserved groups.

You can clearly see the device used, Phoresor II Auto PM850, which I found for around $1k. But I also found a similar, medical-grade device, the Trivarion ActivaDose Phoresor, available here for $250. It seems to be in a family of medical device that is used to deliver water soluble drugs via the skin. More here.
The CBS video is from 2008!

Our Atlanta pain doctors have a new technology — tDCS — to treat pain that doesn’t respond to other pain treatments. It is ideal for many patients suffering from chronic pain because it is effective, inexpensive, painless, non-invasive, non-surgical and requires only 20-minute treatments.

Hmm, are these guys out of the same Michigan University that just published the tDCS paper in ‘Headache’?
Their kit will be Open Sourced. Learn more about Go Flow at http://flowstateengaged.com.
I signed up for the mailing list. If they can really build a no-solder kit for $99 I’m getting one!

This video was made to make our friends laugh. Please do not take this video as a serious attempt at promoting our kit. We sure didn’t.

“We went beyond, ‘OK, this works,'” DaSilva said. “We also showed what possible areas of the brain are affected by the therapy.”

They did this by using a high-resolution computational model. They correctly predicted that the electric current would go where directed by the electrodes placed on the subject’s head, but the current also flowed through other critical regions of the brain associated with how we perceive and modulate pain.

“Previously, it was thought that the electric current would only go into the most superficial areas of the cortex,” DaSilva said. “We found that pain-related areas very deep in the brain could be targeted.”

The present study demonstrates that posterior tDCS can alter visuo-spatial WM performance by modulating the underlying neural activity. This result can be considered an important step towards a better understanding of the mechanisms involved in tDCS-induced modulations of cognitive processing. This is of particular importance for the application of electrical brain stimulation as a therapeutic treatment of neuropsychiatric deficits in clinical populations.